This invention relates generally to a passive start and entry (PASE) system that monitors a LF frequency used to transmit communications between the PASE system and a fob. More particularly, the PASE system sends a signal from the fob to a vehicle to alert a user that noise on the LF frequency may be interfering with the PASE system and the fob communications.
PASE systems perform unlock and start a vehicle without requiring a passenger to have a key. The PASE system communicates an inquiry signal to a fob that the passenger carries. The fob transmits a confirmation signal back to the vehicle, and vehicle doors are unlocked or the vehicle is started when the signal is confirmed. When an occupant leaves the vehicle, the PASE system will relock the vehicle doors when the fob is a predetermined distance from the vehicle.
Currently, the inquiry signal from the PASE system is sent from the vehicle to the fob using an LF signal. The fob receives the LF signal and responds with an inquiry answer that is a RF signal. LF signals are vulnerable to noise that can interfere with the inquiry signal being received by the fob. If no inquiry signal is received, the fob does not perform the requested function. The user would receive an inaccurate “No Fob Detected” message as a result. This problem commonly occurs as a result of certain cell phone chargers or other communication devices that operate at a similar frequency to the PASE system, creating LF noise that interferes with the PASE system signals.
It is therefore desirable to develop and design an improved communication system for passive start end entry systems.